Agency spokesman Mark Toner did not provide details about what those options would be.

He demanded Pyongyang to "refrain from actions that further destabilize the region" by taking concrete steps toward denuclearization.

"The real punch" would come with "stringent" implementation of the sanctions the U.S. has placed on North Korea for more than 60 years, he said. "We're working to in fact implement those to make sure that North Korea feels them."

Toner's comments came in response to media reports that claimed North Korea is preparing a fifth nuclear test.

North Korea has for years threatened to strike the U.S. and its ally South Korea, but Pyongyang's aggressive rhetoric intensified after the country's fourth-ever nuclear test in January and subsequent long-range rocket launch -- which were met with toughened United Nations sanctions.